The mechanisms of carrier capture and escape in a high-power strained quantum-well (QW) InGaAs-InGaAsP-InGaP laser diode have been studied by CW optical spectroscopy. From the temperature dependence of the photocurrent, we deduce that the thermal escape of light holes is the mechanism limiting the carrier escape rate. By measuring the ratio of the electroluminescence signals generated from the confinement layers and the QW's, we show that the onset of a steady state of carrier capture in the QW's is determined by the limitation of the carrier mean free path by inelastic scattering events. Our findings are consistent with the record-high CW output powers reported for 0.97-/spl mu/m emitting laser diodes.